1. Field of the Invention
The present invention relates to an orientational material or substrate (i.e., a material comprising diamond with a surface of specific orientational diamond) which may suitably be used in a variety of devices such as dynamical (or mechanical), electric, electronic and optical devices utilizing diamond, and more particularly, to an orientational material or substrate comprising diamond and a layer comprising another substance disposed on a surface of the diamond having a specific orientational property, and a surface acoustic wave device (hereinafter, referred to as "SAW device") utilizing the orientational substrate. Such a SAW device may suitably be used for an electric, electronic or optical device such as high-frequency filter.
2. Related Background Art
Diamond is used in a variety of devices utilizing its dynamical, electric, electronic or optical characteristic. Specific examples of such a device utilizing diamond may include a SAW device which may suitably be used for a high-frequency filter, etc.
Heretofore, as the SAW device, there is known one having a multilayered structure comprising a diamond thin film and a combination of an electrode and a piezoelectric material disposed on the diamond thin film as shown in Japanese Patent Publication (KOKOKU) No. 38874/1979 (i.e., Sho 54-38874) and Japanese Laid-Open Patent Application (KOKAI) No. 62911/1989 (i.e., Sho 64-62911).
However, in the above-mentioned conventional SAW device utilizing a diamond thin film, when a layer comprising a piezoelectric substance is formed on the diamond thin film, the resultant device utilizing diamond is liable to cause a large propagation loss of surface acoustic wave (hereinafter, referred to as "SAW").